For starters, there's the immense potential of optical radiation in cancer diagnosis and screening - not least when optical interrogation is used as an adjunct to established clinical modalities like CT, MRI and PET (optics+x). A case in point is the US National Cancer Institute's Network for Translational Research in Optical Imaging (NTROI). In a session dedicated to NTROI's research, Brian Pogue, associate professor of engineering at Dartmouth College (Hanover, NH), reviewed the integration of near-infrared spectroscopy into standard MRI and CT instrumentation. While this type of hybrid imaging is still in its infancy, Pogue reckons that using it to guide therapy or to properly individualize the choice of therapy is "the next logical step".

Elsewhere, the network is also pioneering the use of functional optical imaging (specifically, diffuse optical tomography) in tandem with PET. The purpose here is not primary detection of breast cancer, rather the evaluation of a patient's response to therapy and early identification of resistance factors during treatment - information which can be used by doctors to adapt the treatment plan accordingly (see "Multimodal thinking on breast cancer").

If multimodal imaging was a defining theme at BiOS, so too was the push for combined-modality treatments. Indicative of that trend is work on laser therapies to trigger secondary host immune responses, a combination that shows real promise in controlling difficult-to-treat local tumours and metastatic disease at distant sites (see "Photoimmunotherapy: a winning combination?").

Scientists at the University of Oklahoma, for example, presented details of a laser-based treatment that, based on a Phase I clinical study, yields the highest response rate of any therapy for advanced cutaneous melanoma as well as greatly enhanced quality of survival. Called in-situ photoimmunotherapy, the technique combines local photothermal destruction of existing solid tumours with the topical administration of an immune-response modifier (a drug called imiquimod) to trigger an anti-tumour response.

Another conference thread that proved a big draw among delegates was low-light-level therapy (no doubt helped by the fact that it was singled out as an area to watch during Saturday's Hot Topics session). Notable papers reviewed the regenerative effects of laser light in the treatment of spinal-cord injury, as well as laser-induced modulations of the metabolic activities of malignant human-brain-cancer cells. It's early days, but the researchers in both instances reckon the results are further evidence that low-level light is emerging as a promising non-invasive therapy (see "A closer look at low-light therapy").

All told, if BiOS is about one thing right now, it's about technology push. As such, the meeting has a pivotal role to play in ensuring that next-generation optical modalities - both diagnostic and therapeutic - address an identifiable medical need. Beyond that, it's going to fall to photonics researchers and, ultimately, manufacturers to ensure that their optical innovations go on to deliver a price:performance edge versus incumbent clinical technologies.